The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A common way of estimating when it's a good idea to plant geranium is to use the USDA zone info for Spearfish.

Planting Calendar for Geranium

Frost tolerance for geranium:	Not tolerant of frost.
When to plant:	After the last frost has passed.

It's probably not a good idea to plant geranium until after all chance of frost has passed because they are not cold tolerant.

The earliest that you can plant geranium in Spearfish is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant geranium and expect a good harvest is probably August. If you wait any later than that and your geranium may not have a chance to grow to maturity. If you are starting your geranium indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Spearfish. It might get as low as -20°F during the coldest months of winter.

Since the USDA zone info for Spearfish is an average the actual date of last frost will vary from year to year. Since half of the time in Spearfish it frosts late in the year after April 15 be ready to protect your geranium in the event of one of those late frosts.

USDA Zone Info for Spearfish

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Spearfish

You may be interested in your other planting guides for Spearfish.